Automatic clutch release



Oct. 21, 1941. v. B. LOWDER 2,259,824

I AUTOMATIC CLUTCH REL-EASE Filed March 13; 1940 4 Sheets-Sheet l fzg. Z

fig. 5

f] .j 37 J 5 30 I v. B. LOWDER AUTOMATIC CLUTCH RELEASE Oct. 21, 1941.

Filed March 13, 1940 4 Sheets-Sheet 2 Oct. 21, 1941. v. B. LOWDER 2,259,824

AUTOMATIC GL UTCH RELEASE Filed March 13, 1940 4 SheetsSheet 3 Oct. 21, 1941. v. B. LOWDER 2 AUTOMATiC CLUTCH RELEASE Filed March 13, 1940 Q 4 Sheets-Sheet 4' 7 l J 5a 379 Patented Oct. 21, 1941 -UNITED STATES PATENT OFFICE AUTOMATIC CLUTCH RELEASE Vander B. Lowder, Concord, N. C.

Application March 13, 1940, Serial No. 323,838

22 Claims.

This application is a continuation in part of my co-pending application Serial No. 225,191, filed August 16, 1938, as to all matter common to the two applications. The subject matter of these related applications, and common to both, involves improvements in an automatic clutch release adapted to disengage a driving from a driven member upon the rotation of the latter member being retarded or upon an overload being placed upon the driven member.

Therefore, it is an object of my invention to provide an improved automatic release clutch compact in construction and having the minimum replaceable parts. It has been my object to provide means whereby the operative mechanism of the said clutch may be kept continuously bathed in oil.and provide a compact housing adapted to protect the operative members of the said clutch from the accumulation of lint and other foreign matter and adapted to serve as a convenient means for resetting the released coupling to the operative position.

Another object of my invention is to provide improved means, operable upon the driving and driven member becoming disengaged ijor the retention of the same in the inoperative position until manually reset and further providing means for the sounding of an alarm or the breaking of the circuit of the driving motor upon the disengagement of the driving member from the driven member, thereby promptly notifying the operator of trouble rather than depending upon him to discover the difiiculty.

It is a further object of my invention to provide an improved means of coupling the driving member to the driven member, so that wear which normally may occur, between the coupling members, will be automatically taken up, thus assuring a positive driving connection without loose play between the coupling members.

It has also been my object to provide a mechanism readily adaptable wherever an over load release clutch may be desired.

Other objects and advantages of this invention are set forth in the following description, taken with the accompanying drawings; and the novel features thereof are pointed out in the appended claims. The disclosure, however, is illustrative only and I may make changes in detail, especially in' matters of shape, size and arrangement of parts within the principle of the invention, to the full extent indicated by the broad and general meanings of the terms in which the appended claims are expressed.

On the drawings:

Figure 1 is a side elevation of my improved automatic release clutch with the housing for convenience broken away showing the release mechanism,

Figure 2 is a longitudinal section taken along the line 22 of Figure 1.

Figure 3 is a cross section taken on line 33 of Figure 2.

Figure 4 is a longitudinal section of the reset plunger taken along the line 4-4 of Figure 2.

Figure 5 is a cross section taken on-line 55 of Figure 1 broken away in part to show the structure of the engaging lugs.

Figure 6 is a perspective view of the reset plunger.

Figure 7 is a perspective view of the mandrel on which the release mechanism shown in Figure 1, is mounted.

Figure 8 is a perspective view of the triggers.

Figure 9 is a side elevation of a modified specie of my improved automatic release clutch, with the principal housing for convenience broken away showing the release mechanism.

Figure 10 is a longitudinal section taken along the line Ill-40 of Figure 9.

Figure 11 is a side elevation of the mandrel on which the release mechanism shown in Figure 10 is mounted Figure 12 is a further modified specie of my improved automatic release clutch, with the principal housing for convenience broken away showing the release mechanism.

Figure 13 is a longitudinal section taken. along theline l3--l3 of Figure 12.

Figure 14 is a side elevation of the hub on which the release mechanism shown in Figure 12 is mounted.

In the embodiment of my invention illustrated in Figures 1 and 2, there is provided a driving part, namely the gear wheel I, and a driven part comprised by the mandrel 6, Figures 1, 2 and 7. The said mandrel 6, has formed integral therewith, and at the end thereof the laterally projecting annular collar I, having the two bevelsided or V shaped notches 8, formed at diametrically opposite positions along the inner edge of the said collar 1, and having the apex of the said notch 8, extending through to the bevelsided notch 9, formed in the outer edge of the collar I, thereby segmenting the collar 1, into two equal parts. The said mandrel 6, has a socket at one end to receive the end of a spindle or driven shaft II. The said spindle ll, being splined, Figures 2 and 5 to the mandrel 6, by the key I2, held by theset screw I4.

Slidably mounted on the said mandrel 8, is

the driving member or gear wheel I, having formed integral, therewith and at diametrically opposite points, the two axially projecting V shaped lugs or bevel-sided dogs I5, having the ends I6, substantially squared, Figures 1 and 5.

The width of the said V shaped lugs I6 at the widest point or point nearest the driving memher is greater than the greatest width of the V shaped or bevel sided notches 8, but the width of the said lugs or dogs I5 at the,narrowest point or at the end I6 is less than the greatest width of the said notches 8. The bevel sides of. the V shaped .notches 8, and the V shaped dogs I5, are formed at an angle of substantially 45 degrees to the collar 1, Figure l.

The bevel-sided or V shaped dogs I5, are adapted to engage in part, the bevel sides of the notches 8', and to thereby positively connect the driving member, gear wheel I, and the driven member mandrel 6, in power-transmitting relationship.

Upon the driving and driven member being in engaging position the inner wall of the annular collar 1, and the wall of the gear wheel I, are spaced ,apart, as shown in Figure 1, since the dogs I5, only in part engage the V shaped notches 8. The bevel sides of the V shaped notches 8, form a friction surface co-acting with the bevel sides of the V shaped dogs l6, to form sliding flts with the dogs I5, whereby upon an obstruction or an overload being applied to the spindle or to the driven member 6, the V shaped dogs I5, will slide along the bevel surface of the V shaped notches 8, up on and along the inner edge l1, of the collar 1, the squared end I6, oi. dogs I5, riding along the aforesaid edge I1, and the driving member gear wheel I, moving longitudinally on the mandrel 6, placing the driving and driven members in disengaged positions.

Formed at the opposite end of the gear wheel I, and integral therewith is the axially projecting flange l8, having provided the internal annular groove 28.

Acting against the longitudinal movement of the said gear wheel is the expanding helical spring 2|, coiled about the mandrel 6. The said mandrel 6, has apertured from opposite sides thereof, the longitudinal slot 22, adapted to receive the oppositely mounted looking or latching triggers or levers 23, positioned longitudinally therein, and fulcrumed on the roller 24, disposed within the slot 22, between the levers 23, and intermediate the ends of the said levers.

Slidably mounted on the said mandrel 6, are the collars 25 and 26. The collar 25, is positioned at the fore end of the aforesaid expansion spring 2|, and contiguous with the flange I8, of the gear wheel I, while at the opposite end of the said spring 2|, is placed the collar 26. Adapted to engage the said collar 26, are the outwardly curved rear portions 21, of the levers 23. The levers 23 are pivotally mounted on the roller 24 in such a manner that when the said portions 21 project fully out of the said slot 22, the V shaped fingers 28 provided at the forward ends of the said levers 23 are positioned fully within the said slot 22. In the latter position the collar 25 is adapted'to slide longitudinally on the mandrel 6 over the fingers 28 positioned within the slot 22 and thereby secure the said levers 23 within the slot 22. The curved portion 21, of the levers 23, engaging the collar 26, mounted at the rear end of the expansion spring 2| secures the collar 26, and the expansion spring 2|, from moving longitudinally rearward, and thereby secures the expansion spring 2|, in the compressed position.

With the spring 2| and the collar 26, thus held, the forward expansive force of the spring 2|, normally maintains the dogs I5, in engaging position with the bevel sided notches 8. However, upon an obstruction or overload being applied to the driven shaft II, the dogs I5 will disengage from the bevel sided notches 8, as previously explained. Moreover, the gear wheel I together with the collar 25 will slide longitudinally rearward on the said mandrel 6 so as to expose the annular groove 20 in the flange I8 for engagement with the fingers 28 of the levers 23. Further, the expansive force of the spring 2| will force the collar 28 against the outwardly curved rear portions 21 of the levers 23 and will thereby cause the said portions 21 to be projected inwardly into the slot 22, pivoting the levers 23 on the roller 24 and projecting the forward V shaped fingers 28 of the levers 23 outward from the slot 22 and into the groove 20. The said fingers 28 will thereby engage the said gear wheel I and lock the said gear wheel I in a disengaging position from the collar 1.

Moreover upon the collar 26 forcing the end portions 21 of the levers 23 into the slot 22, the said portions 21 will release the collar 26 and permit the said collar 26 to slide longitudinally rearward on the said mandrel 6 under the compression of the spring 2| and thereby release the said expansion spring 2|.

Limiting the aforesaid longitudinal movement of the collar 26, under the expansive force of the spring 2|, and functioning as an end thrust bearing for the levers 23, is the small metal bar 28, disposed across the rearward end of the slot 22, Figures 1 and 2. The said bar 28, having the opposite ends thereof, projecting laterally from opposite sides of the said mandrel 6, and the collar 26, thus limited by the projecting ends of the bar 29, is positioned immediately covering the end portions 21, of the levers 23, thereby locking the said portions 21, in the slot 22. In the latter position it will be readily apparent that the driving member gear wheel I, will revolve on the mandrel 6, with the flange I8 turning on the fingers 28 positioned in the groove 28. Further the fingers 28 will thereby lock the dogs l5 of the said gear wheel I out of engaging relation with the bevel sided notches 8 of the collar 1, thus securing the mandrel 6 and the gear wheel I in a disengaging relation.

In order to reset the aforesaid, release clutch, there is provided 'a reset plunger 30, slidably received in the socket 3|, formed at the end of the mandrel 6, Figures 1, 2, 4 and '1. The said reset plunger 30, has formed integral therewith, a pair of longitudinally extending parallel arms 32, which are slidably received in slots 33, formed in the mandrel 6, at right angles to the slot 22. The free ends of the arms 32, have laterally projecting lugs 34.

Upon depressing the reset plunger 38, the laterally projecting lugs 34, engage the collar 26, sliding the same longitudinally forward on the mandrel 6, thereby uncovering the end members 21, of the levers 23, mounted in slot 22, compressing the expansion spring 2|, and upon the bevel-sided dogs I5, of the gear wheel I, be-

ing adjusted opposite the bevel-sided notches 8, the expansive force of the spring 2|, will force the said dogs l5, and notches 8, into engaging position.

The bevel-side N3, of the V shaped fingers 28, forms a sliding fit with the annular groove 28, whereby upon the ends 21, being uncovered by the longitudinal forward movement of the col? lar 28, the expansive force of the spring 2|, will cause the flange l8, to slide along the bevel side plunger 88, having its opposite end engaged in the socket 8|, of the mandrel 8, which spring normally holds the reset plunger in the inoperativeposition. A cap 81, fits over the end of the mandrel 6, to hold the reset plunger in place, being adapted to engage the lugs, and thereby limiting the outward longitudinal movement of the said reset plunger 88. The said cap 81, is secured to the mandrel 6, by the set screw 88.

The metal housing 88, encloses the aforesaid mechanism, being screwed on the collar 25, as

' at 48, and at the end of the said housing 88,

there is provided an opening to receive the head 4|, of the reset plunger 88. Apertured at 44, in the head 4|, of, the said plunger 38, Figures 2 and 6, is the longitudinally extending passage ,48, having the opening 42, formed at the'oppo- -site end thereof in the side of the plunger 88, Fig.

ures 1, 2, 4 and 6. The said passage 48, serving as a means for placing oil in the housing 88, for keeping the release mechanism enclosed thereby, properly oiled. It is readily apparent that in the normal position of the plunger 88, the opening 42, of the passage 48, is closed by the wall of the housing 38, but upon depressing the plunger 38, the opening 42, in the side of the plunger 38, is no longer closed and oil may be readily inserted through the passage 48, into the housing 38.

The second specie of my invention illustrated by Drawings 9, 10 and 11, operates substantially the same as the form of my invention previously described. However, in the second form of my invention the gear wheel I, is shown without the flange l8, previously described, formed integral therewith, and'in place of the fiange l8, having the groove 28, formed therein, there is provided the collar 45, having formed therein the internal annular groove 46, having the internal beveled edge 41. Thus, upon axial movement of the gear wheel I, sliding the collar 45, longitudinally rearward and exposing the groove 46, to engagement with the fingers 28, of the levers 28', the said fingers 28, are projected out as previously described, from the slot 22, and lock in the annular groove 46, engaging the internal beveled edge 41., It is readily apparent that since the gear wheel I, is not mechanically connected to the said collar 45, the groove 46, does not revolve with the gear wheel I, on the projecting fingers 28, as in the case of the annular groove l8, shown in the first species of my invention.

A cap 48, fits over the end of the mandrel 48, being held in place by a screw threaded countersunk bolt 58, disposed in a screw threaded hole 5|, located at the end of the mandrel 48, the said hole 5|, extending inward to the end of the slot 22.

The metal housing 52, encloses the aforesaid mechanism, being screwed on the collar 45, as at 88, and the opposite end of the said housing 52, has an opening to receive-an auxiliary. housing 84. At the end of the said housing 54, there is provided a screw threaded hole 55, adapted for the insertion of oil into the housiw 82 and 84. The said oil'hole 58, may be readily closed by means of the screw threaded bolt 88.

Formed at the opposite end of the said housing 54, is a laterally projecting annular flange 51.'i'ormed integral with the said housing 84. An expanding helical spring 88 is coiled about the housing .84. The said spring 88 is engaged at one end by the flange 51 and at the opposite end by the annular felt washer 68'secured by the internal annular flange 58 formed integral with and at the end of the principal housing 52. The felt washer 68 is adapted to prevent the escape of theoil from the housing 52.

The expansive force of the spring 58, against the annular flange 51, of the auxiliary housing 54, causes the said housing 54 to be projected into the housing 52. The inward movement of the said housing 54 is limited by the laterally Projecting annular flange provided on the collar 26. Thus, with the release clutch in coupled position, as shown by Figures 9 and 10, the spring 58, holds the auxiliary housing 54, firmly against the projecting flange provided on the collar 26, lessening thereby any noise or rattle in the housing 54. Further, upon the disengagement of the coupling'means, the said spring 58, acts as a shock absorber against the expansive force of the spring 2|, upon the disengagement of the collar 26, from the end members 21, of the levers 28'.

In resetting the release mechanism, it will be readily apparent, that while the expansive force of the spring 58, is less than that of the spring 2|; since the expansive force of the spring 58, will be acting against the spring 2|, it will be necessary to apply less manual force against the housing 54, to slide the collar 26, longitudinally forward, so as to compress the spring 2| to reset the release clutch. The expansive force of spring 2|, thus acting against the, collar 45, causes force to be in turn applied by the internalbeveled ed e 41, on the beveled surface l8, of the fingers 28, forming therewith a coacting friction surface, whereby the said fingers 28, are slid into the slot 22, the opposite ends 21, of the levers 28, being free to be fulcrumed out of the said slot 22,'by the collar 26, having been previously moved longitudinally forward by the depressing of the auxiliary housing 54. Upon the disengagement of the fingers 28, the collar 45, under the expansive force of the spring 2| is projected longitudinally forward, together with the gear wheel I, and the coupling means engaged as previously explained.

A third specie of my invention is illustrated by Figures 12 and 13, which show the said release clutch in the disengaged position. The latter form of my invention provides a hub or mandrel 6|, through which there is longitudinally extended a shaft or spindle H. The said spindle II is splined to the hub 6|, by the key l2,

held by the set screw |4. Disposed adjacent one end of the said hub 6|, is the collar 1, as previously described, and at the same end of the hub 6|, there is provided an annular raised part 02, on which is slidabiy mounted the gear wheel I, the aforesaid raised part '2, having an annular beveled side 83. Further,- slidably mounted on the hub Ii. and contiguous with the gear wheel I, is the collar 04, having a socket I, provided with anlinner annular side coupled to the collar 1 of hub OI, by means of the notches I, as previously explained, the annular raised part 82, is slidably received in the socket 65 of the collar I, the beveled side I, of the socket SI, being adapted to engage and fit contiguouswith the beveled side 03, of the CC. Upon the dols ",ofthe gearwheel l,being raised part 02. Upon the coupling means becoming disenga ed as previously explained, the

..collar I4, is moved longitudinally rearward on forced into the slot 22 the said collar 50 will slide longitudinally rearward over the parts 2! locking the parts 21 in the said slots! and the levers 23" in the latter fulcrumed position as shown'in Figure 13. A screw threaded cap 10 is screwed on the end of the hub II as at H in such a manner as to limit the rearward longitudinal movement of the collar [I on the hub I,

The aforementioned levers 13'', in the latter embodiment of my invention are fulcrumed on the separate rollers 88, mounted on either side of the hub I, in the separate slots '1.

The metal housing I3, encloses the aforesaidmechanism, being screwed on the collar M, as at 12. The said housing II, has provided at the end thereof, an opening for receiving the auxiliary housing I4. At the end of the said auxiliary housing 14, there is similarly provided an opening 15, through which there is extended the shaft or spindle Ii. A feltwasher'ld, disposed in the annular groove 11, is provided to prevent the loss of oil from,the said housing 14.

At the opposite end of the said housing ll, and formed integral therewith is the laterally projecting annular flange ll, adapted to engage the annular felt washer I9, mounted on the said auxiliary housing 14, and the internal annular flange 80, formed integral with and at the end of the principal housing 13. The felt washer l9, likewise serves to prevent the escape of the lubricating oil from the said housing II.

In resetting the release mechanism, the auxiliary housing 14, is depressed, causing the collar 60, to move longitudinally on the hub 8|, exposing the portions 21, of the levers 23", causing the spring II, to be compressed and the fingers 2!, to become disengaged from the internal bevel side 86, of collar 64, thus disengaging the collar 64, from the fingers 28, and re-engaging the dogs IS, with the notches 8, as previously explained.

Mounted on the collar 69, is the screw threaded adjustable collar ll, adapted to engage the screw threads on the collar 69. By means of the collar ii, the compression of the expansion spring 2|, may be readily adjusted.

As shown in Figure 12, there is provided in the housing II, a screw threaded hole closed by and for disengaging the the bolt II, which hole is adapted for the insertion of oil into the said housing.

While the form of my invention as shown in Figures 12 and 18 does not show the auxiliary spring ",disclosed in the second form of lnv invention and illustrated by Drawings 9 and 10,

on the mandrel I, is or hub ll, thereby disengaging the gear wheel I, from the shaft or spindle' ll the circuit switch 88, is .automatically closed sounding an alarm or breaking the circuit of the driving motor thus informing the operator of trouble rather than depending upon the operator to discover the trouble. In operation, the end of the actuating arm 84, rests against the laterally projecting annular flange formed on the forward collar of the release mechanism and indicated in Figure l, by numeral 25, Figure 9, by numeral II, and Figure 12, by numeral It. One contact of the switch It is stationarily mounted while the opposite contact is mounted at the free'end of the said actuating arm 84. Upon rearward axial movement of the said collar, the actuating arm I, is pivoted at ti, by the axial movement of the laterally projecting annular flange aforesaid, closing the circuit as shown in Fi ure 12.

It will further appear that as the bevel sides of the dogs i5, and notches I, are worn by friction, the spring II, will force the dogs ll, further into the notches ll, thereby providing a convenient means for the taking up of slack in the coupling members and. holding the coupling members firmly in the enga ing position without loose play between the members. Further,

since the co-acting friction surfaces of the bevel sided notches I, and the bevel sided dogs II, are of small area, the said coupling members may be disengaged'with the minimum force. The tomerequired to disengage the said coupling members is primarily dependent upon the expansive force of the spring 2|, acting against the axial movement of the gear wheel I.

Having thus described my invention, what I claim as my invention and desire to secure by Letters Patent is:

1. The combination comprising a mandrel having driving and driven members mounted thereon, releasable means for engaging the said members, an expansion spring mounted on the said mandrel, means for holding the said spring compressed to normally hold the said driving and driven members in ensuing relationship, means for releasing the said expansion spring said driving and driven members upon a predetermined overload on the driven member and means for compressing the said spring to return the driving member to a reengaging relationship with the driven member.

2. The combination comprising a mandrel having driving and driven members mounted thereon, releasable means for engaging the said members, an expansion spring mounted on the said mandrel, means for holding the said spring compressed to normally hold the said driving and driven members in engaging relationship, means forreleasing the said expansion spring and for disengaging the said driving and driven members upon a predetermined overload on the driven member, including means for holding the said driving member disengaged from the driven member.

3. The combination comprising a mandrel having driving and driven members mounted thereon, releasable means for engaging the said members, an expansion spring mounted on the said mandrel, means for holding the said spring compressed to normallyhold the said driving and driven members in engaging relationship, means for releasing the said expansion spring upon a predetermined overload on the driven member.

4. The combination comprising a mandrel having driving and driven members mounted thereon, releasable means for engaging the said members, a primary expansion spring mounted on the said mandrel to normally hold the driving 7 and driven members in engaging relationship and an auxiliary spring mounted on the said mandrel acting in opposition to one end of the primary expansion spring.

5. The combination comprising a mandrel having driving and driven members mounted thereon, releasable means for engaging the said members, a primary expansion spring mounted on the said mandrel, means for holding the said spring compressed to normally hold the said driving and driven members in engaging relationship, means for releasing the said expansion spring upon a predetermined overload on the driven member and an auxiliary spring mounted on the said mandrel acting in opposition to one end of the primary expansion spring.

6. The combination comprising a mandrel having driving and driven members mounted thereon, releasable means for engaging the said members, a primary expansion spring mounted on the said mandrel, means for holding the said spring compressed to normally hold the said driving and driven members in engaging relationship, 7

means for releasing the said expansion spring and for disengaging the said driving and driven members upon a predetermined overload on the driven member, mounted on the said mandrel an auxiliary spring acting in opposition to one end of the primary 'expansion spring and manually operable means for compressing the said primary expansion spring to return the driving member to a reengaging relationship with the driven member.

'7. The combination comprising a mandrel having driving and driven members mounted thereon, releasable means for engaging the said members, a primary expansion spring mounted on the said mandrel, means for holding the said spring compressed to normally hold the said driving and driven members in engaging relationship, means for releasing the said expansion spring and for disengaging the said driving and driven members upon a predetermined overload on the driven member, including means for locking the said primary expansion spring in an inoperative position and an auxiliary spring acting in opposition to one end of the said primary expansion spring.

8. The combination comprising a work spindle, a mandrel connected to said spindle, a collar formed on said mandrel having a notch, a driving wheel slidably mounted on said mandrel having a lug for engaging said notch, an expansion spring for normally holding said notch and lug in engaging position, an internal annular groove formed in the said driving wheel, and the said mandrel having pivotally mounted levers adapted said mandrel to normally hold the driving and driven members in engaging relationship, means for disengaging the said members upon a predetermined overload on the driven member, means for locking the said spring in an inoperative position, a principal housing enclosing the said locking means and an auxiliary housing slidably mounted at the end of the principal housing manually operable as a means to reengage the driving and driven members.

11. The combination comprising a mandrel having driving and driven members thereon, a primary expansion spring mounted on the said mandrelto normally hold the driving and driven members in engaging relationship, means for disengaging the said members upon apredetermined overload on the driven member, means for lockingthe'primary expansion spring in an inoperative position, a principal housing enclosing the said locking means and an auxiliary housing slinably mounted at the end of the principal housing, a spring mounted on the said auxiliary housing acting in opposition to one end of the pri mary expansion spring and to the outward movement of the slidably mounted auxiliary housing, the latter housing serving as a manually operable means for the reengagement of the driving an driven members.

12. The combination comprising a work spindle, a mandrel connected to said spindle, a clutch collar carried by said mandrel, a driving wheel slidably mounted on said mandrel, means carried by said wheel for engagement with said clutch collar, an expansion spring mounted on said mandrel for normally holding said wheel and clutch collar in engaging position, levers pivotally mounted in a slot in said mandrel, the said levers having ofl'sets at one end and V shaped fingers at the opposite ends, a collar slidable on said mandrel and movable by said spring to engage the oflsets of said levers, whereby said levers are pivoted to engage the V shaped fingers in a groove in the said wheel when the wheel is disengaged from the clutch collar.

13. The combination comprising a work spindle, a mandrel connected to said work spindle, a driving wheel slidably mounted on said mandrel, the said driving. wheel having a flange at one end provided with an internal annular groove, 7

lugs projecting from the opposite end of the said wheel, a clutch collar carried by said mandrel, the said clutch collar having notches to receive said lugs, a pair of collars slidably mounted on said mandrel, an expansion spring mounted on said mandrel between said collars, a pair of levers pivotally mounted in a slot formed in said mandrel having offsets at one end and projecting V shaped fingers at the opposite ends, said fingers being adapted to engage in the bore of one of said collars when said spring is compressed and said lugs are engaged in said clutch collar, and

bers being adapted to rotate freely thereon, an

expansion spring mounted on the said hub to normally hold the driving and driven members in engaging relationship, means for disengaging the said members upon a predetermined overload on the driven member, means for locking the said spring in an inoperative position, a principal housing enclosing the said locking means andan auxiliary housing slidably mounted on the spindle at the end of the principal housing manually operable as a means to reengage the driving and driven members.

15. The combination comprising a mandrel having driving and driven members mounted thereon, the said members comprising a clutch collar carried by said mandrel and a wheel slidably mounted on the said mandrel, V shaped bevel sided notches being formed in the said clutch collar adapted to engage in part V shaped bevel sided lugs having the ends thereof squared and projecting axially from the said wheel, the

width of the said V shaped lugs being at the widest point greater than the greatest width of the V shaped bevel sided notches, and the width of the V shaped bevel sided lugs at the narrowest point being less than the greatest width of the V shaped bevel sided notches, an expansion spring mounted on said mandrel for'normally holding the said lugs and notchesin engaging position, the said lugs in engaging position separating the said clutch collar and wheel.

16. The combination comprising a hub having a spindle connected thereto axially projecting through a bore formed in the said hub, driving and driven members mounted on the said hub. the said members comprising a clutch collar carried by said hub and a wheel slidably mounted on the said hub, V shaped bevel sided notches being formed in the said clutch collar adapted to engage in part V shaped bevel sided lugs having the ends thereof squared and projecting axially from the said wheel, the width of the said V shaped lugs being at the widest point greater than the greatest width of the V shaped bevel sided notches and the width of the V shaped bevel sided lugs at the narrowest point being less than the greatest width of the V shaped bevel sided notches, an expansion spring mounted on said mandrel for normally holding the said lugs and notches in engaging position, the said lugs in engaging position separating the said clutch collar and wheel, and means for locking the said spring in an inoperative position upon a predetermined overload on the driven member.

17. The combination comprising a work spindle, a mandrel connected to said work spindle, a driving wheel slidably mounted on said mandrel, lugs projecting axially from the said wheel, a clutch collar carried by said mandrel having notches to receive said lugs, a pair of collars slidably mounted on said mandrel, an expansion spring mounted on said mandrel between the said collars for normally holding the said collars under spring tension and the said wheel and clutch collar in engaging relation, one or the said collars being positioned between the said expansion spring and the said driving wheel and the latter collar having an internal annular groove. a pair or levers plvotally mounted in a slot formed in the said mandrel, the said levers having ofisets at one end and projecting V shaped fingers at the opposite ends, the said V shaped fingers being disposed within the collar positioned between the driving wheel and the said expansion spring, and the said ofisets disposed in-the path of movement of the other collar in such a manner as to engage the latter collar under the tension oi! the said spring, whereby upon axial movement of the said driving wheel the said levers are pivoted under the tension of the said spring in such a manner as to engage the fingers oi the said levers in the said annular groove formed in the said collar mounted between the driving wheel and the said expansion spring.

18. An overload clutch comprising driving and driven members, releasable means for engaging the said members, an expansion spring operatively connected at one end to one of the said members in such a manner as to normally hold the said driving and driven members in engaging relationship, means provided at the other end oi. the said spring to hold the said expansion spring compressed, said means being released upon a predetermined overload on the driven member.

19. An overload clutch comprising driving and driven members, releasable means for engaging the said members, a mandrel having one of the said members slidably mounted thereon, an ex-- pansion spring operatively connected at one end to the said slidably mounted member and adapted to hold the said driving and driven members in engaging relationship, a locking means operatively connected to the other end of the said expansion spring, whereby upon axial movement of the said slidably mounted member the said spring is locked at the said one end against eflecting clutch engagement.

20. An overload clutch comprising driving and driven members, releasable means for engaging the said members, a mandrel having one of the said members slidably mounted thereon, an expansion spring for normally holding the said driving and driven members in enga ing relationship, a pivoted lever one end of which having means for engagement with the said expansion spring and the other end of said. lever having means to engage the said slidably mounted member in such a manner as to lock the said driving and driven members in a disengaging relationship upon axial movement of 'the said slidably mounted member.

21. An overload clutch comprising driving and driven members, releasable means forengaging the said members, a mandrel having one of the said members slidably mounted thereon and the said member having a flange at one end provided with an internal annular groove, a lever pivotally mounted in a slot in said mandrel, the said lever having an onset at one end and a finger at the opposite end, a spring, a collar slidable on said mandrel and movable by said spring to engage the said offset of the said lever whereby said lever is pivoted to engage the said finger in the said groove in the flange aforesaid upon the disengagement of the said driving and driven members.

22. An overload clutch comprising driving and driven members, releasable means for engaging the said members, a mandrel having one of the said members slidably mounted thereon, resilient means for normally holding the said driving and driven members in engaging relationship, the said mandrel having a slot formed therein, a lever pivotally mounted in the said slot, the said lever having an offset at one end and a finger at the opposite end, a collar slidably mounted on the said mandrel and tension means for the said collar whereby the said collar is held in engaging relationship with the ofl'set of the said lever, 10 

